Normally, base station antennas are limited in beam forming abilities by the fact that they only are configured to radiate their beam in one particular direction. The antenna coverage is normally either sector or omni depending of the antenna type chosen. Typical sector antennas are patch antennas. Typical omni antennas are dipole antennas. Traditional base stations with sector beam antennas integrated need to be mechanically orientated to direct the antenna sector beam toward wanted coverage area.
Typically, installations of antennas for base transceiver stations may comprise either sector antennas that are integrated in the front of the base transceiver station, or omni antennas, which are mounted on the top or the bottom of the base transceiver station.
Such traditional base station antenna solutions can work quite well for many scenarios, but they are not very flexible. One would not install the omni antenna on the base transceiver station on a site where coverage is needed just in a limited spatial region, it would be much more suitable there to use the sector antenna solution. Moreover, the sector antenna normally has its maximum directivity directed in the direction normal to the front side of the base transceiver station. Since the base transceiver station normally is installed on a wall this implies a problem, since the sector beam of the base transceiver station then is bound to radiate in a direction normal to the wall surface; a limitation that is not always positive. To direct the beam in other direction than from the wall, the base station need to be mechanical tilted towards wanted direction of coverage. Indeed, attempts have been made to create beam-steering functionalities on flat panel sector antennas, but the beam-steering abilities achieved are quite limited due to the constraints of the flat antenna architecture.
It appears that base station antennas require further development for improved flexibility and adaptivity to requirements within a cell.